A photoacoustic imaging method that enables photoacoustic images to be displayed at high speed is provided. The photoacoustic imaging method scans a subject with a light beam, detects acoustic waves generated within the subject due to the scanning of light to obtain acoustic wave detected signals, and generates volume data that represent three dimensional photoacoustic images of the subject based on the acoustic wave detected signals. Photoacoustic projection images projected in the direction of irradiation depth of the light are generated, prior to the volume data being generated and concurrently with the scanning of the light. The photoacoustic projection images are displayed.